Analog to Digital (A/D) converters that have a very large dynamic range must be driven with high voltage analog signals having very low distortion to preserve their dynamic range. For example, A/D converters that produce ten or more bits must be driven with extremely linear amplifiers. Linearity in excess of 60 dB (equivalent to about 0.1 percent distortion) is required for a ten-bit A/D converter. This sort of linearity is very difficult to obtain over required typical voltage ranges, such as one to two volts. This is especially difficult when low power consumption and high sampling rates are desired.
Thus what is needed is an A/D converter subsystem with a very large dynamic range. What is also needed is an A/D converter subsystem that does not have to be driven with high voltage analog signals to achieve high linearity. What is also needed is an A/D converter subsystem that uses less power, and can be fabricated on a single monolithic chip.